Mail Archives: geda-user/2014/07/07/12:34:39
On 07/06/2014 11:41 PM, Gabriel Paubert wrote:
> On Sun, Jul 06, 2014 at 01:16:31AM -0400, DJ Delorie wrote:
>>> The peninsulas neck down to less than the minimum copper width rule.
>> I typically expand the pad clearances until such necks vanish.
> I did this until holes were added to polygons. Now I use holes to
> precisley control where the copper pour stops. But holes have
> they own problems (moving them, mostly, they are rigidly linked
> to the containing polygon), so I only draw them as the last step,
> when everything else is essentially ready for production.
With my current problem, progress > beauty, so I expanded the pad
clearances :-/
>>> So, first off, I'm surprised that the Cu polygon allows Cu to pour into
>>> a space less than the minimum width rule.
>> Polygon pours are handled poorly in pcb.
> <snip>
>
>>> Third, is it legal to specify zero-width Pad[] elements in a footprint,
>>> and assign clearance values, in order to composite some clearance into
>>> the footprint?
>> I think this is fine, although perhaps a tiny non-zero width might be
>> needed. I don't know if these cause outputs in the gerber file,
>> though, so be careful.
> I really recommend using polygon holes in this case, I did this before
> holes were supported, and this was much worse, despite the defects
> of the holes listed above.
Worse how?
I spent a few minutes looking at the code. The gerber output has a
check in the aperture selection code where if a zero-width aperture is
requested, it returns NULL, which (if the comments are to be believed)
suppresses any output in the gerber file for zero-thickness elements.
I'm not sure where to look for how a zero-thickness pad might cause
phantom shorts or how it interacts with route blocking. Clues welcome.
>
> Gabriel
Thanks for your comments. Very helpful.
-dave
>
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